Folding knives are invaluable tools that are used in many aspects of everyday life, and there are many, many types and styles of folding knives. A “manual” folding knife is a very traditional type of tool in which the knife blade is manually movable by the user between a closed or stowed position in which the sharp edge of the blade is held safely within the handle, and an open position in which the blade is extended in an operable position. Most modern versions of manually operated folding knives include locking mechanisms that lock the blade in the open position—the safety benefits of such locks are obvious. There are innumerable variations on these basic themes.
Automatic folding knifes are nearly as ubiquitous as manual folders. These knives include some type of a mechanism—almost always a spring-driven mechanism—that drives the blade from the closed position toward the open position when the user activates the automatic triggering mechanism, typically by pushing a button or analogous activating mechanism. Generally speaking, in a knife that has an automatic opening mechanism the blade is held in the closed position by a latched trigger mechanism. When the blade is in the closed position the blade is under a constant “pre-load” pressure from a spring mechanism. When the trigger is released, the blade is automatically driven by the spring mechanism into the open position. As with most modern versions of manual knives, most automatic folding knives include locks that lock the blade in the open position. When the user “unlocks” the blade to move it from the open position to the closed position, the rotation of the blade as it is pivoted to the closed position reloads the spring mechanism so that the blade is ready to fire again when desired.
Most folding knives, whether manual or automatic, incorporate some kind of a mechanism that holds the blade or working implement in the closed position in which the sharp edge of the blade is held safely within the handle. There are many known mechanisms for retaining blades in the closed position, and there are obvious reasons why such mechanisms are used. Among other reasons, blade-retaining mechanisms prevent unintended opening of the knife and thus promote safety. As noted, most folding knives also include mechanisms that lock the blade in the open position, again, primarily as a safety feature.
Manual and automatic knives have many uses and can be used in many different settings, and that has led to a demand expressed by many knife users for knives that are operable in dual modes, both automatic and manual. There are benefits to be had in knives that have dual modes of operation and there are a few known dual mode knives. For instance, dual mode knives are described in U.S. Pat. Nos. 7,603,778 and 8,046,923. These knives combine the functionality of both manual and automatic knives and are thus very versatile.
Nonetheless, there is a continuing need for improved mechanisms for enabling dual operational modes in a folding knife, manual and automatic.
The present invention comprises a folding knife having mechanisms that facilitate use of the knife in dual operational modes. In a first modality, the knife is opened and closed manually. In a second modality, the knife is fully automatic. The user is able to switch between modalities with manipulation of a slider bar in the space between handle halves. In a preferred embodiment, the knife may be switched from the automatic mode into the manual mode, and vice versa, only when the blade is in the open position. This is an important safety feature and is very useful from an operational perspective because when the blade is in the open position it is under spring pressure that continues to push the blade toward the open position; the user must make a conscious decision with the blade in the open position to operate the knife in either the manual or automatic mode.
The knife utilizes a torsion spring around the pivot shaft that connects the blade to the handle. The spring drives the blade from the closed to the open position in the automatic operational mode and a switch mechanism is used to alternately engage and disengaged the spring from the blade. One end of the spring is fixed to the handle and the other end of the spring interacts with a specially formed grooved portion in the tang of the blade when the switch mechanism is in the automatic position. A bar that is part of the switch mechanism has a surface that is operable to engage the spring so that the spring is lifted out of the grooved portion in the tang of the blade when the switch is in the manual position.